Heads-up displays, also known as head-mounted displays or near-to-eye, allow a wearer to view a scene while relevant information is overlaid on the scene, so that the wearer looking through the heads-up display simultaneously sees both the scene and the relevant information. For example, a pilot looking through a heads-up display while landing an airplane simultaneously sees the airport ahead (the scene) through the heads-up display while the heads-up display projects information such as speed, heading and altitude (the relevant information) that the pilot needs to land the plane.
Heads-up displays provide a powerful platform for mobile computing, but because the scene and relevant information are displayed only in the headset, the experience is strictly personal and limited to the headset wearer. If the wearer wishes to share what they are viewing, their only option is to pass the headset to another person. This can only be done with one person at a time and not done in a group setting.